/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System;
using IndexReader = Lucene.Net.Index.IndexReader;

namespace Lucene.Net.Search
{
	
    /// <summary>A {@link HitCollector} implementation that collects the top-sorting
    /// documents, returning them as a {@link TopFieldDocs}.  This is used by {@link
    /// IndexSearcher} to implement {@link TopFieldDocs}-based search.
    /// 
    /// <p>This may be extended, overriding the collect method to, e.g.,
    /// conditionally invoke <code>super()</code> in order to filter which
    /// documents are collected.
    /// 
    /// </summary>
    public class TopFieldDocCollector : TopDocCollector
    {
		
        /// <summary>Construct to collect a given number of hits.</summary>
        /// <param name="reader">the index to be searched
        /// </param>
        /// <param name="sort">the sort criteria
        /// </param>
        /// <param name="numHits">the maximum number of hits to collect
        /// </param>
        public TopFieldDocCollector(IndexReader reader, Sort sort, int numHits) : base(numHits, new FieldSortedHitQueue(reader, sort.fields, numHits))
        {
        }
		
        // javadoc inherited
        public override void  Collect(int doc, float score)
        {
            if (score > 0.0f)
            {
                totalHits++;
                hq.Insert(new FieldDoc(doc, score));
            }
        }
		
        // javadoc inherited
        public override TopDocs TopDocs()
        {
            FieldSortedHitQueue fshq = (FieldSortedHitQueue) hq;
            ScoreDoc[] scoreDocs = new ScoreDoc[fshq.Size()];
            for (int i = fshq.Size() - 1; i >= 0; i--)
                // put docs in array
                scoreDocs[i] = fshq.FillFields((FieldDoc) fshq.Pop());
			
            return new TopFieldDocs(totalHits, scoreDocs, fshq.GetFields(), fshq.GetMaxScore());
        }
    }
}